It is known that the physical properties of fabrics can be modified by certain treatments. For example, fabric may be treated in order to modify its physical properties either in an industrial pretreatment or during laundering.
Fabrics in general, and cotton in particular, are prone to the formation of creases before, during and after laundering and drying. In order to remove such creases from the fabric, a considerable amount of time and effort must be spent ironing upon each occasion of laundering and drying. The terms “crease” and “wrinkle” and related terms, such as “anti-crease” and “anti-wrinkle”, refer to non-permanent deformations in the fabric which can be removed by flattening at elevated temperature and moisture (eg, by ironing) and are used synonymously herein.
Some of the previous attempts to address the problems of crease formation with regard to fabrics have been based on the use of insoluble particulate materials.
U.S. Pat. No. 3,892,681, for example, discloses the use of granular, substantially water-insoluble starch particles having a diameter between 1 to 45: m in detergent compositions. Such particles are said to impart anti-wrinkling and ease of ironing benefits in addition to other fabric conditioning properties.
A detergent composition featuring a substantially water-insoluble particulate material with a diameter from about 5 to 30: m is described in U.S. Pat. No. 4,051,046. The particulate material may be a glass, ceramic or polymer-based bead, or a starch that has been treated with a hydrophobic agent to reduce its water solubility. In order to permit ironing, the particles must have a melting point above 150° C. These compositions are said to confer a range of fabric benefits, including anti-wrinkling and ease of ironing.
The use of smectite clay as a softening agent is disclosed in U.S. Pat. No. 3,936,537. In this document, the clay is combined with a quaternary ammonium salt, which confers anti-static benefits, and a dispersion inhibitor consisting of a solid organic material, in a detergent compatible composition.
Smectite clay is also used in the fabric-softening detergent compositions disclosed in U.S. Pat. No. 4,062,647. Again the clay is said to impart improved softening and/or antistatic characteristics.
A fabric softening detergent composition comprising a synthetic non-soap detergent, builder salt and clay is disclosed in GB 1400898. The clay, added for softening benefits, is a three-layer smectite-type clay with an ion exchange capacity of at least 50 meq/100 g. The combination of builder salt and clay is described as helping prevent agglomeration of the clay, thus allowing efficient deposition of the clay on fabric. In GB 1428061, a similar fabric softening composition is disclosed with a water-insoluble quaternary ammonium salt present as an anti-static agent. The smectite-type clay, responsible for imparting softness benefits, has a particle size below 50 microns and an ion-exchange capacity of at least 50 meq/100 grams.
In U.S. Pat. No. 5,443,750, clay, which may be smectite clay, is used in conjunction with an enzyme in a detergent composition to afford increased softening properties.
EP-A-0 381 487 describes the use of liquid detergent compositions in which a clay (an aluminosilicate eg, smectite) is treated with a barrier material, selected from a siloxane, a polysiloxane, a polyacrylate, dialkyl citrate, alkoxylated dialkyl citrate, alkoxylated glycerol mono- and di-stearates, and alkoxylated N-alkyl alkanolamides, prior to incorporation of the clay into the formulation.
The treatment of a range of water insoluble materials, including clay, with an organosilicon compound bearing a quaternary ammonium group is taught in U.S. Pat. No. 4,557,854. The organosilicon groups are grafted onto the surface of the clay particles and, therefore, will be bound to the silicon atoms in the layers of the clay by way of Si—O linkages. The effect of the treatment is described as being to increase the cleaning power of conventional organic surface-active agents.
The treatment of cotton fabrics with cross-linking agents, such as butane-1,2,3,4-tetracarboxylic acid (BTCA), is known to impart anti-wrinkle properties. However, such treatments tend to make the fabric stiff and relatively easy to tear.
The present invention aims to provide a system which is applicable to the treatment of fabric in order to provide desirable properties in the fabric. Desirable properties which may be achieved in the fabric as a result of treatment with a composition according to the invention include, for example, one or more of the following benefits: anti-wrinkle, increased softness, better shape, improved texture, improved colour (including surface colour definition), better antistatic properties, reduced friction, better comfort in wear, increased water absorption or increased water resistance and/or repellence and better durability (ie, resistance to wear, including anti-pilling and anti-fuzz properties). In a particularly preferred embodiment, the compositions of the invention are used for reducing the extent of creasing of fabric, such as before and/or during and/or after laundering.